In 2004 McWilliam admitted to an audience at the Edinburgh International Book Festival that she had struggled with alcoholism.[2] In early 2006, McWilliam began to suffer from the effects of blepharospasm and became severely visually impaired as a result. This illness caused her eyelids to be permanently shut, although her eyes were still perfect. In 2007 she spoke about the experience of blindness at the Edinburgh International Book Festival, and in 2008 she wrote an article about her situation for the Scottish Review of Books.[3] In 2009 she underwent an operation which harvested tendons from her leg in order to suspend her eyelids open, thus curing her blindness.

In an article in The Sunday Times, McWilliam described her two years of blindness and the pioneering surgery that restored her sight. She went blind, she added, after years of writer's block — her last novel appeared in 1994 — but she refound her voice while she was blind and dictated to a kind young friend what turned out to be a memoir, What to Look for in Winter, which was published in 2010. She is now at work on a novel.[4]